Preheat oven to 350˚F (180˚C) and line a baking sheet with parchment. Grease 6 (5 inch, 12.5 cm) circle molds or ramekins.
In a large bowl, cream together the butter and sugar. Mix in the flour, baking powder, and salt.
In another bowl, beat together the milk and egg. Add to the flour mixture and combine to create a dough.
On a lightly floured surface, knead the dough until smooth. If too crumbly, add a little more milk. If too sticky, add a little more flour. Divide the dough into 6 equal pieces. Roll each piece into a ball, press into a thin circle, and place on prepared baking sheet. Top each circle with a greased mold or inverted ramekin. Bake in preheated oven for 20 minutes. Remove the ramekins, flip the rolls, and cook for another 10 minutes. Transfer the rolls to a wire rack to cool completely.
Preheat oven to 350˚F (180˚C). Slice each cooled roll in half and place on a baking sheet, cut side up. Bake until toasted through and golden, 10-15 minutes. Turn off the heat, slightly open the oven door, and allow to cool in the oven.
Once cooled, store the beschuiten in an airtight container until ready to serve.